Daily kimchi consumption associated with reduced obesity risk, study reveals

06 Feb 2024 --- Kimchi, the beloved Korean dish known for its spicy and tangy flavors, may hold the key to lower obesity risk, particularly in men, according to a recent study. The research suggests that consuming up to three daily servings of kimchi, including the popular radish kimchi, is associated with a reduced prevalence of obesity.

Nutrition Insight caught up with two of the study’s authors, Dr. Sangah Shin of Chung-Ang University and Dr. Sung Wook Hong from the World Institute of Kimchi, to discuss the study’s results, which shed light on the potential health benefits of incorporating this traditional fermented food into daily diets.

“Ingesting probiotic lactic acid bacteria derived from kimchi during its fermentation process has been linked to a decrease in body weight, body mass index (BMI) and waist circumference in adults with overweight or obesity,” Hong and Shin reveal. “Additionally, kimchi exhibits an anti-obesity effect and helps reduce lipid accumulation.”

“Common spices used in kimchi, such as garlic, onion and ginger, have been associated with anti-obesity effects. Garlic intake has been linked to a reduction in waist circumference and BMI, primarily affecting body weight and fat mass. Previous animal studies indicate that compounds found in garlic can decrease lipid accumulation in adipocytes, specifically 3T3-L1 cells. Onions, which contain quercetin, a flavonoid, have been shown to reduce adipocyte hyperplasia.”

Kimchi and obesity
The researchers sought to uncover whether regular consumption of kimchi could be linked to a decreased risk of overall and abdominal obesity, which is known to be particularly detrimental to health. To investigate this, they analyzed data from the Health Examinees study, which included a large cohort of Korean adults over 40 years old.

Hong and Shin highlight that since, in South Korea, kimchi is not only enjoyed in its raw form but also incorporated into a variety of cooked dishes, such as soups, stews and stir-fries, its culinary diversity presents challenges in accurately measuring kimchi intake using Food Frequency Questionnaires (FQQs). They note that, as FQQs typically focus on frequency, they may not fully capture the range of portion sizes associated with kimchi’s various preparations.

The study, published in BMJ Open, assessed participants’ dietary habits and measured their height, weight, waist circumference and BMI. For the study, obesity was defined as a BMI above 25, while abdominal obesity was defined based on specific waist circumference criteria of greater than or equal to 90 cm in men and greater than or equal to 85 cm in women.

“To assess the independent relationship between kimchi consumption and obesity, we controlled for potential confounding variables, including age, household income level, education level, marital status, alcohol consumption, smoking status, physical activity and nutritional factors,” the researchers highlight. 

Consumption of radish kimchi was linked with lower abdominal circumference in men and women.“These nutritional factors encompassed total energy intake, energy-adjusted sodium intake, energy-adjusted potassium intake, fiber intake, cooked rice and other kimchi consumption.”

The J-shaped curve
The results revealed a J-shaped curve in relation to kimchi consumption and obesity risk. This means that eating more than five servings of kimchi a day may also be associated with an increase in the prevalence of obesity.

“Our results displayed a J-shaped curve, suggesting a potential increase in body weight with the consumption of more than five servings of kimchi,” Shin and Hong underscore. “It’s essential to note that consuming a substantial amount of kimchi may imply an overall increase in food intake and any observed effects cannot be solely attributed to kimchi.”

While higher kimchi intake was associated with increased overall energy and nutrient consumption, eating up to three daily servings of total kimchi was linked to an 11% lower prevalence of obesity compared to those who consumed less than one serving, leading the team to endorse the incorporation of kimchi into daily diet regimens.

“Kimchi’s versatility allows it to be incorporated into dishes from various countries,” say Hong and Shin. “Boost your kimchi intake by preparing diverse dishes such as kimchi quesadilla, kimchi lasagna and kimchi pasta.”

“We recommend including kimchi in your diet for improved health and potential weight loss. Based on our findings and the 2020 Dietary Reference Intakes for Koreans, we recommend kimchi consumption of up to three servings per day.”

Radish kimchi and abdominal circumference
The study also found that consuming below-average quantities of kkakdugi kimchi (radish kimchi) was correlated with a 9% lower prevalence of obesity in both sexes.

Furthermore, consuming 25 g per day for men and 11 g per day for women of radish kimchi was associated with an 8% lower risk for men and an 11% lower risk for women for abdominal obesity, when compared to participants with no consumption.

“Radish contains glucoraphenin and glucoraphasatin, which have been demonstrated to possess anti-cancer, anti-lipid accumulation and anti-obesity properties, among others,” the researchers underscore. “Moreover, the consumption of vegetables has been linked to a reduction in abdominal fat.”

“As kimchi is not only delicious but also includes radish as an ingredient, incorporating kimchi into our meals can contribute to an increased overall vegetable intake.”

Nutritional power of kimchi
Kimchi, a traditional fermented dish made from vegetables like cabbage and radish, is renowned for its low-calorie content and high nutritional value, including dietary fiber, lactic acid bacteria that enhance the microbiome, vitamins and polyphenols.

The kimchi-making process includes soaking cabbage and radish in brine and seasoning them generously with red pepper powder, garlic, onion, ginger, scallion, salt-fermented shrimp sauce (saeujeot), fermented fish sauce (aekjeot) and glutinous rice.The natural probiotics and effects of the ingredients in kimchi have all been shown to reduce the risk of obesity.

The researchers point out that previous studies have highlighted the anti-obesity effects of certain bacteria found in kimchi. For instance, ginger and its primary compound, 6-shogaol, have exhibited the capacity to hinder the process of adipogenic conversion that occurs during adipogenesis. Additionally, the bacteria present in kimchi has been shown to have its own health benefits.

“In a cell-based experiment, Lactobacillus brevis and L. plantarum, isolated from kimchi demonstrated an anti-obesity effect, suppressing adipocyte differentiation and reducing lipid accumulation by downregulating the expression of adipogenesis-related genes,” explain Shin and Hong.

More research needed
While this observational study cannot establish causation, it does offer insight into the potential benefits of kimchi consumption, especially concerning obesity risk. The results underscore the importance of dietary habits and their impact on health, even in the context of traditional foods like kimchi. 

However, the researchers acknowledge that further research is needed to understand the relationship fully and to determine if these findings apply to populations outside of Korea. It’s important to note that kimchi’s high salt content, though counteracted by its potassium content, should be consumed in moderation for overall health.

“Our research has shed light on the potential relationship between kimchi consumption and obesity and, while our findings are insightful, it is important to acknowledge the complexity of dietary habits and their impact on health,” Hong and Shin conclude. “Further studies with larger sample sizes, diverse populations and extended follow-up periods can enhance the robustness of our observations.”

“Additionally, investigating specific mechanisms underlying the observed effects and exploring potential variations in kimchi preparation and consumption methods can contribute to a more nuanced understanding. We remain committed to advancing research in this area to provide a comprehensive perspective on the interplay between kimchi consumption and obesity.”

By William Bradford Nichols